There are a host of banknote or payment validators which receive a paper substrate and advance the paper substrate through a validation section and if acceptable, move the substrate to a banknote cassette. The banknote cassette includes a stacker mechanism to displace the received banknote into a storage area where the received paper payments are retained in a stacked configuration.
Many of the known banknote or payment cassettes use a scissor type linkage for moving a stacker plate through receiving guides to displace a banknote received in a guide arrangement and move the paper substrate into the storage area to one side of the guide arrangement. An example of the scissor type stacking mechanism is shown in our U.S. Pat. No. 6,241,240. In this patent, a rotary cam is used to control movement of the stacking mechanism and also control movement of the guides to provide a more efficient stripping of the banknote from the guides. Other arrangements merely use the scissor type stacking arrangement to move through the stationary guides.
Various arrangements have been proposed for efficient movement of the stacker plate through the guides and into the storage arrangement. These mechanisms require power particularly when the storage arrangement has received a number of banknotes approaching the capacity of the cassette. Typically the storage area includes a pressure plate having a spring bias for biasing the plate towards the guides. The stacker plate when forced through the guides, overcomes the spring bias and moves the stack of banknotes, and on the return stroke of the stacker mechanism, the spring bias returns the stack to a stop position against the guides. Thus, the stacker mechanism must overcome the spring bias, in combination with the inertia and resistance of the stack of banknotes. The power requirements increase as the cassette approaches its capacity. Furthermore, it can be appreciated that the power variation during the stroke of the stacker plate also varies. The initial power of the stacker plate to move from an initial position to one side of the guides and through the guides is only opposed by any resistance offered by the single banknote being stripped from the guides. Once the stacker plate contacts the stack of previously stored banknotes or paper substrates, then additional power is required.
The prior art has used a number of different arrangements such as a gear train for driving of the stacker plate or a rotary cam arrangement as shown in our earlier patent or a push actuator projecting from the rear surface of the cassette. It is desirable to operate the stacker plate with a relatively low power drive to reduce the cost of the banknote acceptor and the cassette. It is also desirable to have a space efficient, relatively narrow drive to maximize the storage compartment. Typically, a banknote validator will have several banknote cassettes to allow withdrawal of a full cassette and insertion of an empty cassette. Therefore, it is desirable to have a cassette that can be manufactured in a cost effective manner.
The present invention provides an improved drive linkage associated with the scissor type mechanism for stacking of a paper substrate received in the guides.